To study the effects of wet sludge amount on the coal-fired boiler parameters by blending flue gas dried sludge, a thermal calculation and analysis of 300 MW power plant are studied in this paper based on the energy conservation equation. Under the load of BMCR, 75%THA, 50%THA, and 30%THA, the influences on flue gas extraction ratio (extracted from low-temperature superheater outlet), thermal efficiency, and coal consumption are calculated and analyzed. The results show that blending sludge will cause the deterioration of the boiler’s main parameters. The variation increases as the boiler load and the amount of wet sludge decreases. For comprehensive consideration of engineering cost, boiler parameters and the influences on environmental facilities, the percentage of wet sludge and fuel should be controlled below 10% under different load conditions. The influence on the sludge-coal blending combustion with extracted flue gas under full load condition is revealed and a mathematical conclusion is obtained.
Keywords wet sludge, blending amount, flue gas desiccation, blending combustion, coal-fired boiler